curveball

Etymology

curve + ball

noun

1. (baseball) A forespin pitch thrown by rotating the index and middle fingers down and resulting in motion down "curve"
   He bit on a curveball in the dirt.
2. (by extension, chiefly US) An unexpected turn of events initiated by an opponent or chance; an exception or outlier.
   Life has thrown him a few curveballs.
   The season’s first episode, “Bart Gets an F,” got the highest ratings in its history, but “Treehouse of Horror” was the real curveball: a genre-busting effort that proudly punched above the show’s expectations. 2015-03-10, David Sims, “Without Sam Simon, 'The Simpsons' Wouldn't Be What It Is Today”, in The Atlantic
   There are two curveball nominations, one perhaps a popularity bid and the other a credibility bid. The popular one is Bieber’s Purpose. 2016-12-06, Spencer Kornhaber, “The Culture Wars in the Grammy Album Nominations”, in The Atlantic
   But from time to time, June throws up a curveball, in the shape of unusual and hard to predict meteorological events. 2017-06-13, Stephen Moss, “June likes to throw a curveball now and again”, in The Guardian
   And I think that’s an example of where faced with a seemingly intractable political reality, technology produces a solution that is a total curveball and not that imaginable a few decades ago. 2021-06-11, Ezra Klein, “Sam Altman on the A.I. Revolution, Trillionaires and the Future of Political Power” (32:37 from the start), in The Ezra Klein Show (podcast), spoken by Sam Altman

verb

1. (baseball) To throw a curveball.
   Even though the haughty physics professors at the elite school ridiculed his declaration that he could make a baseball curve, Cummings just laughed it off and said, “I curveballed them to death,” according to Frederick Ivor-Campbell. 2006, William F. McNeil, The Evolution of Pitching in Major League Baseball, McFarland, page 21
   The news curveballed him. He'd been hamstrung and schizzed all the preceding weeks. He brooded in his den. 2009, James Ellroy, Blood's a Rover, Random House, page 566